My Roomba 550 has a charging error 5. Tech support says the only option is to buy a "refurbished" robot from them. Do I really have to buy someone elses broken, repaired robot, or is there a way to repair my own? I am moderatly hardware savvy with computers, and rescued my old robot twice. Now I'm sorry I gave the old one away.

Check the output dc voltage of your Power Supply Unit. It should measure 22.5 volts. How are you charging your Roomba? Do you use a homebase? If you use a homebase, disconnect it and try charging by connecting the PSU directly into the charging jack on the side of the Roomba.

I purchased my iRobot brand new from a US seller on eBay in Dec 2009. It was shipped promtly to Australia, where we use 230V.

First thing, I plugged the power supply (only) into a step-down voltage transformer (output 110V), and the iRobot power supply started emitting smoke... - the original power supply died that day.

Then I purchased a "Universal" iRobot Powersupply (110-240V input) on eBay from a Singapore Reseller (half price compared to Australia pricing), and it all worked beautifully for almost 2 months. (this one may have been modified, but it bears the embedded iRobot logo in the plastic and all)

After 2 months of daily usage it started reporting "Charging Error 5", and the battery pack seemed to die. It would charge EXACTLY 30 minutes, then report the error. After trying all the resets and all the other recommended solutions I could find on the internet, the battery finally didnt charge at all (Not even the red LED lights come one now, when the original battery pack is installed).

So, I purchased another battery pack on eBay, this time from a seller in Utah, the new one is a NiMH, 14.4V 3300mAh. (original battery was a Ni-CD, 2200mAh).

This new battery charged on the first day, and the robot was happily running around for 1 hour, before returning to the base station, to charge again. It charged for app. 1 hour before reporting the same error. I tried resetting the iRobot again and all that, but now it will only charge for 20 minutes at a time, and the robot only manage to run for 5 minutes – which is hardly sufficient to clean even a corner of the room.

I must have done something like 20 resets by now, and left the battery out for up to 24 hours, to completely drain the power and all, yet none of these solutions have provided any improvement.

I also wrote iRobot, on their website, 2 weeks ago, but haven’t heard a thing back from them.What should I do?

Unfortunately I dont have a voltage meter, so before I can proceed on that, I would have to find a place where they can help me with that. But before doing so, is there anyone in here, who, based on my description have an idea what could be wrong? And even better, could advise me a solution to solve the problem?

The charging err 5 is difficult to narrow down. Without a voltmeter you cannot verify the power supply is presenting the correct voltage to the Roomba. So at this point you could possibly have a defective PSU or a failed charging system component on the PCB or the battery is marginal/defective.

cp1972 wrote:I purchased...{550} brand new from a US seller on eBay in Dec 2009. ...was shipped... to Australia, where we use 230V.

You have no idea of how that 550 came to be in the hands of an eBay seller, I presume. You probably assume (about all that can be done) that the unit was never used by a prior owner, such as for a 30-day trial, then returned for credit.

For all you know, its PSU may have been damaged before the eBay seller acquired that Roomba.

...I plugged the power supply (only) into a step-down voltage transformer (output 110V),

Output-voltage is one important parameter when specifying or talking about a step-down xfmr, but, it is also necessary to specify its power handling capability, in terms of watts, or volt*amps.

If "watts" is less than required for the job, the xfmr is the item one may expect to smoke. If watts are greater than required, then money may have been wasted. Another effect that accompanies higher than needed wattage, is secondary voltage will run a few percent higher than nominal, when the load (watts) is less than nominal (because output voltage is not regulated by a transformer). I would be interesting to know that xfmr's no-load voltage, and the voltage when powering a ~30W load.

... and the iRobot power supply started emitting smoke... {&} died that day.

I cannot fathom how a step-down transformer can damage a Roomba PSU, except for a case in which the xfmr's power rating is grossly in excess of that required for this job. Such a xfmr would be too heavy for you to lift (for it to exhibit a too high no-load VAC) and too expensive! If anyone can explain how a properly rated (voltage ratio and power rating) xfmr can harm a switch-mode PSU, I wish they would say something.

Then I purchased a "Universal" iRobot Powersupply (110-240V input) ..., and it all worked beautifully for almost 2 months. ...After 2 months of daily usage it started reporting "Charging Error 5", and the battery pack seemed to die. It would charge EXACTLY 30 minutes, then report the error.

This is the hot season down-under, and that may be causing a PSU shut-down.

... After trying all the resets and all the other recommended solutions I could find... the battery finally didnt charge at all (Not even the red LED lights come one now, when the original battery pack is installed).

That would suggest the PSU is not powering Roomba into Charging-Mode, and suggests a duff PSU. Then you say:

...I purchased another battery pack ... a NiMH, 14.4V 3300mAh. (original battery was a Ni-CD, 2200mAh). {and} This new battery charged on the first day, and the robot was happily running around for 1 hour, before returning to the base station, to charge again. It charged for app. 1 hour before reporting the same error. ... but now it will only charge for 20 minutes at a time, and the robot only manage to run for 5 minutes ...

Which suggests: The good initial performance with #2- batt might have been obtained via its pre-purchase state of charge, after which your duff PSU failed to actually charge the battery. Its hard to be sure.

...and left the battery out for up to 24 hours, to completely drain the power ...

24 hours would not have resulted in much self-discharge, fortunately for you and batt-#2! FYI, you never want to "completely" drain all charge (Roomba only permits charge to be removed until terminal voltage reaches 12V), NOT zero-volts).

I also wrote iRobot, on their website, 2 weeks ago, but haven’t heard a thing back from them.

Either no reply will be sent, or, if one is received it will be a form letter telling you to deal with iRobot's off-shore contractor in Australia.

What should I do?

You must decide to get technically involved, or just guess at what item to replace, buy it and try it.

vic7767 is right, Carsten. If you hope to find out what has gone wrong, you need to get a DMM, ASAP, and learn how to use it. On 2nd thought, I'd put that at #2, since the first thing to do is take care of batt-#2 -- it may be discharged farther than is safe for it. Consider these tasks as starters:

1) Find some way to add charge to batt-#2:__a) Disconnect and store the Home Base out of sight.__b) Get a rough idea whether the PSU is outputting enough power to effect some charging, by temporarily contacting a household lamp (bulb) to its live dc-power plug. Use a 60W to 100W, incandescent light bulb. Hold the coaxial plug's outer barrel in one of the candelabra-base screw-thread grooves, while touching a short jumper wire between the plug's center-contact and the bulb's central contact. If the filament glows red (it won't be bright), that will demonstrate the PSU is somewhat capable of passing current through a Roomba battery. If that check works OK, proceed to (c)__c) Plug the charging-PSU in Roomba's side charging jack and test for proper charging activity.

2) Now is when you will need the DMM, if not bought already.

3) If (1-c) fails to work, you could try charging in a manner that is independent of the robot. Here is how TechGuy does that with a 4XXX Roomba battery:viewtopic.php?p=72971#p72971Doing that same setup with a 5XX battery will be more trouble/tricky, and there are more possibilities for you to wreck something -- so don't proceed w/o first getting, and understanding additional instructions. You will need to know how to use that DMM for this work.

4) Using your new DMM, measure the output voltage from your PSU. Do that with no load conected, then do it with the above lamp-loading (you could probably go up to a 200W to 300W lamp -- my 100W lamp test drew only 1/3rd amp, but the SMPS-PSU should provide 1.25A before its voltage falls below its no-load level). Tell us what you measure.

5) I take it that you have not perused this forum's READ FIRST Sticky, so go there, find, then d/l the 500 Series Service Manual, a pdf file.__a) Search for universal, and read a few words about your PSU.__b) Search for Err5, and read about things that cause that error. You will see that a hot PSU might withdraw (alluded) from charging and cause the 30-minutes time-out due to proper charging current not being maintained.__c) Find and learn how to run the BiTs (Built-in-Tests), since that will become necessary if the PSU can be given a clean bill of health.

So, I had time to check up on these issues today. I started the day by performing the incandescent light bulb check - no result was visible. Then I purchased a voltage meter.

The voltage meter couldn’t read a steady current on the PSU, it was fluctuating rapidly up and down between approx. 10V and reading a maximum of 17.7V .

I also tried measuring the battery packs, and the original one now has a reading of 4.68V and the one I purchased as a replacement had a reading of 14.36V.

The Seller of the universal PSU had already contacted me via email last night after reading my post here, so we have been in touch today.

With instructions from the seller, I checked the Capacitor, which showed up to be from a faulty batch. As a result of this the seller has posted me a new PSU free of charge.

Considering the warnings about how to get the packs charged to avoid damage, I don’t have much idea how to do it at the moment. I have a Sony Vaio Laptop charger that delivers 19.5V/4.7A – I am in doubt if this is enough to charge the battery or not, and also, - since the plug doesn’t fit – I would have to go with the direct connection (as described in the other posting).

However, I don’t know which is +/- on the battery pack as there are no markings, nor on the round plug on the power supply (i.e. the inside is the + or the - ?). (Maybe I do need to check the manual a litte better, although I thought I had it all read and understood) But if anyone can give me some quick advice on how to identify the poles, and also a head up if the 19.5V would work to charge it up a bit, I would greatly appreciate it!? (Thanks in advance for this!)

As to the original iRobot power supply and the smoke emitting; I used a travel inverter I purchased in Japan, when I was returning home after living there for 3 years. It has the following specs: Input: 220-240V / 50/60Hz & Output: 110 V AC / 100W MAX I have used it with the appliances I purchased while living there since 2005 without problems. And no, its not heavy at all! I guess that means the original PSU had a problem…

Status now is that the new PSU has been shipped and I am awaiting it to check that it solves the problem (P.S. good customer service by the way!).

cp1972 wrote:...The voltage meter couldn’t read a steady current {voltage} on the PSU, it was fluctuating rapidly up and down between approx. 10V and reading a maximum of 17.7V .

Definitely a dud!

I also tried measuring the battery packs, and the original one now has a reading of 4.68V and the one I purchased as a replacement had a reading of 14.36V.

I doubt you will be able to restore batt-#1. Batt-#2 should come out of this bad start-up, OK.

...Considering the warnings about how to get the packs charged to avoid damage, I don’t have much idea how to do it at the moment. I have a Sony Vaio Laptop charger that delivers 19.5V/4.7A – I am in doubt if this is enough to charge the battery or not, and also, ... – I would have to go with the direct connection (as described in the other posting).

Too late at night for me to get into that, but I can give some ideas about it tomorrow.

... I don’t know which is +/- on the battery pack as there are no markings,...

The pair of contacts located central in the pack connect to the pack's 10k ohms (25C) thermistor -- keep voltage away from them. The two contacts which are in-line with a row of cells are the plus and "minus" ends of two cells (at ends of the 12-cell pack. I'll borrow one of vic7767's pix so you can see how those two cell ends just peek through that plastic frame:

vic has the plus terminal marked (+), but you can tell visually by noting the 9mm diameter raised contact that is surrounded by a white insulator. The other contact is the butt end of the neighbor cell.

... nor on the round plug on the power supply ...

Use your DVM to check it. More often than not, the outer barrel will be the zero-volts side (referred to as (-)), and the center contact will be positive wrt to the barrel.

...and also a head up if the 19.5V would work to charge it up a bit,...

That voltage should take it most of the way -- putting battery voltage into a safe region. However, a word of caution. A discharged battery can draw a lot of current at start of charging, and this one might task a high fraction of that PSU's 4.5A capability! No sweat for the PSU, but I would not like to stress my battery that way. I think it would be wise to figure out some way to connect some ballast resistance in series with that charging loop.

You would like to limit charging current to less than 1.5A, and you have a 'sink' (battery) at 14.4V, and a 'source' (PSU) at 19.5V, so you have about 19.5 - 14.4 = 5V to drop across the resistance. With 1.5A running through the resistance, and 5V across it, R_ballast = 5 / 1.5 = 3.3 ohms, or could be slightly larger. R_ballast will dissipate 1.5A * 5V = 7.5 watts (that's HOT), so you would like to select that resistance value in a package that handles several time 8W, say a 25W resistor. I doubt you will have anything like that lying about the house. I'll give it further thought tomorrow.

To charge the 500 series battery directly, I use crocodile clips to make the contact to the battery terminals as show in the photo. For the positive terminal, clip the black plastic at 45 degrees in order for it to make contact with the positive terminal. The clip can go vertical to the negative terminal.

To ensure that the clips are making good contact with the terminals, the voltage should be between 17V and 20V during charge. It should be lower than the power supply no load voltage (22.5V) and higher than the battery no load voltage.

Gordon wrote:... I think it would be wise to figure out some way to connect some ballast resistance in series with that charging loop. ... I doubt you will have anything like that {3-ohm, 25W power resistor} lying about the house. I'll give it further thought tomorrow.

I can't come up with a simple approach to providing that ballast-resistor. Something would have to be purchased, which could be looked upon as a waste for a one-time application. Instead of using that resistor, I have an alternate process you could try. Call it "burst-charging with temperature and voltage guidance". Here's how I would do it:

2) Measure the resistance of the battery's thermistor while at room temperature (expect the value to be somewhat less than 10k ohms, maybe closer to 6k if the house is warm), and draw a short vertical line across the R vs T curve aligned to the measured value.

3) Make up the charging setup as TechGuy shows, however, it would be good to know how much current is being delivered by your laptop's PSU, so inject and ammeter (20A range) into the loop (that'll tie up your DMM, which will be periodically needed for resistance checks, hence, be sure to arrange for simple electrical R&R of the DMM).

4) Power up the PSU and monitor current. (It will start high, but reduce in a matter of minutes).

5) Start a minutes-timer running.

6) If current is two-amps, or less, charge for ~15-minutes. However, IF current is greater than two amps, charge for ~5 minutes. Note: The battery contains a 4A (resettable) polymer-fuse. Even if the laptop-PSU feeds its full current into the battery, I would not expect the fuse to open for many tens of (maybe a hundred) minutes. That data can be looked up.

7) Upon time-out, remove charging power.

8) Quickly disconnect the DMM, switch it over to its resistance function to permit a quick reading of thermistor-resistance. Make a side note of that value. IF any measurement is 3k ohms, or less, abort further charging (unless you wish to reduce each charging period to just a few minutes, as an attempt to reach step (10)).

9) Wait a few minutes, say three to five (you are waiting for thermal equilibrium to establish), then repeat the resistance check (don't be surprised to find a lower resistance [increased temperature]). Note: While this waiting is going on, its a good time to break away to do other things, since there would be no harm in allowing the battery to cool enough that thermistor resistance matches that in (2).

10) Repeat (9) until resistance is at, or higher than (arbitrarily) 5k ohms, then switch the DMM to DVM-mode and measure the battery's terminal voltage. If V_batt > 17.5V, abort further charging. Dismantle the setup.

11) Loop on (3) through this step (11).

Or, you could just wait for your replacement Roomba-PSU to show up, then charge the battery normally!

Hi, having the same problem as the original poster so i though i would revive this thread instead of starting a new one. I get a charge error 5 after about 30mins of charge on the base. My 550 charges fine plugged in and i get about 1 hour and 1/2 of run time. I have checked the voltage from the power supply and it is about 22.45V with a DMM. THen voltage is about 2.8V at the base with no load on it. I am going to conect some wires to the base while the roomba is charging from the base so i can get a reading on the DMM. I assume i should get about 22V from the DMM while the roomba is charging on the base?

Am i right in assuming that there is nothing wrong with the power supply or the battery as the voltage is within limits from the PSU and the battery is getting about 1 and 1/2 run time so is it the base itself or the PCB?

Any help will be appreciated.

Oh i got my 550 refurbished from US and i am in Australia and i have modified my PSU for a 220-240v power supply.

I removed the battery, and noticed some corrosion on the terminal on the logic board. I scraped of the little bit with a flat head screwdriver, replaced the battery, and the 16 hour charge started. Once complete, it's working like a champ, I know this is a bit obvious, but hope this helps someone!

I have the same Error 5 problem, MY roomba will eventually turn green I'll try to start it and it will just give me the red uh oh, and the battery would die. Also I'm using a older model Charger , The same charger that charges the 400 series roomba which is .5 less Voltage then the 500 series. The charger works great on the 400 series.

The 500 model Roomba has a newer charging system program that is not as forgiving (component wise) as the earlier 4XXX models. You might consider investing in a PSU for the 500 model. You can also consider testing the stored voltage level of the battery and perform a load test on it.